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linux/tools/bpf/bpftool
Kuan-Wei Chiu f04e2ad394 bpftool: Fix undefined behavior in qsort(NULL, 0, ...)
When netfilter has no entry to display, qsort is called with
qsort(NULL, 0, ...). This results in undefined behavior, as UBSan
reports:

net.c:827:2: runtime error: null pointer passed as argument 1, which is declared to never be null

Although the C standard does not explicitly state whether calling qsort
with a NULL pointer when the size is 0 constitutes undefined behavior,
Section 7.1.4 of the C standard (Use of library functions) mentions:

"Each of the following statements applies unless explicitly stated
otherwise in the detailed descriptions that follow: If an argument to a
function has an invalid value (such as a value outside the domain of
the function, or a pointer outside the address space of the program, or
a null pointer, or a pointer to non-modifiable storage when the
corresponding parameter is not const-qualified) or a type (after
promotion) not expected by a function with variable number of
arguments, the behavior is undefined."

To avoid this, add an early return when nf_link_info is NULL to prevent
calling qsort with a NULL pointer.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240910150207.3179306-1-visitorckw@gmail.com
2024-09-10 11:40:55 -07:00
..
bash-completion bpftool: Add bash-completion for tcx subcommand 2024-07-29 12:54:04 -07:00
Documentation bpftool: Fix typos 2024-09-09 15:57:52 -07:00
skeleton
.gitignore
btf.c bpftool: Improve btf c dump sorting stability 2024-09-06 14:06:30 -07:00
btf_dumper.c
cfg.c
cfg.h
cgroup.c
common.c
feature.c bpftool: fix some typos in bpftool 2024-09-05 13:07:47 -07:00
gen.c bpftool: improve skeleton backwards compat with old buggy libbpfs 2024-07-09 19:03:05 -07:00
iter.c
jit_disasm.c
json_writer.c
json_writer.h
link.c
main.c
main.h
Makefile
map.c
map_perf_ring.c
net.c bpftool: Fix undefined behavior in qsort(NULL, 0, ...) 2024-09-10 11:40:55 -07:00
netlink_dumper.c
netlink_dumper.h
perf.c
pids.c
prog.c bpftool: Fix typo in usage help 2024-07-17 22:45:58 +02:00
struct_ops.c
tracelog.c
xlated_dumper.c tools/bpf: Fix the wrong format specifier 2024-07-30 13:41:20 -07:00
xlated_dumper.h